Re: Have I found a bug?

*To*: mathgroup at smc.vnet.net*Subject*: [mg84223] Re: Have I found a bug?*From*: dh <dh at metrohm.ch>*Date*: Fri, 14 Dec 2007 07:02:35 -0500 (EST)*References*: <fjtgdu$7hm$1@smc.vnet.net>

Hi Louise, both are correct. To check, one must get the original function by taking the derivative of Log[- answer] answer2= answer1 Sqrt[-1] = I answer1. Log[-answer2] = Log[- I answer1]= Log[I]+ Log[-answer1] The additional summand Log[I] is eliminated by the derivative. hope this helps, Daniel Louise Hoffman wrote: > Dear readers, > > When I calc. this in Mathematica 5.2 > > g[x_] := 1 - x^2 > h[x_] := -x > Exp[-Integrate[ (D[g[x], x] - h[x])/g[x], x ] ] > > it returns > 1/Sqrt[-1+x^2] > > where I would expect > > 1/Sqrt[1-x^2] > > Have I found a bug, or have I made a mistake? > > Lots of love, > Louise >